The number of performance events can be counted when using a performance monitoring counter provided in a central processing unit (CPU). For example, when the execution of an instruction is counted as a performance event, the total number of instructions executed by the CPU can be obtained. The total number of instructions executed is useful as an index for indicating the performance of the CPU.
The performance of a CPU can also be measured by trace or simulation methods. However, these measurements may impose a greater load on the CPU that is running the programs to be measured.
Japanese Laid-open Patent Publication No. 10-254739 and Japanese Laid-open Patent Publication No. 07-334395 are known as examples of prior art.